As conducive to an understanding of the invention, it is noted that in known tension control devices, the carriages supporting the bearings of a deflecting roller are moved by means of spindles or chains, there being provided, for the purpose of maintaining uniform tension, a connecting shaft reaching from the "leader" side to the "drive" side of the paper handling machine, assuring synchrony of the carriages without travel-length difference. In order to effect a correction of so-called "off" belts or screens so that the distribution of tension becomes linear over the entire width of the belt or screen, it is also known to equip the connecting shaft with a mechanical clutch so that, for instance, by unplugging a pin, the connection is temporarily interrupted in order to achieve a carriage movement differing in distance traveled on the "leader" side and the "drive" side. The thus established uniform belt or screen tension is kept up by means of the re-engaged connecting shaft.
In order to be able to correct the runoff of the belt or screen edges, it is known to provide a pivotably mounted guide roller whose bearings are adjusted more or less as a function of the correct running of the edges, such as through pneumatic control devices. It is not possible with such known belt or screen runoff controls to influence the belt or screen tension so that, in addition to the control devices for the correct running of the edges, separate tension control devices are always required in known paper handling machines.